← Kvist home
Documentation

Testing#

Kvist's test package is a small layer over Odin's core:testing. It gives you Lisp-shaped test declarations, assertion context, table checks, and fixtures while still using Odin's ordinary test runner underneath.

Import it as:

(import t "kvist:test")

Run test files with:

./kvist test path/to/file.kvist

A Small Test#

(package tests)

(import t "kvist:test")

(t.deftest arithmetic
  (t.is (= (+ 2 2) 4)))

t.deftest lowers to an Odin @(test) proc. Inside the test body, t is the current ^testing.T.

A string immediately after the test name becomes the generated proc docstring:

(t.deftest parses-empty-input
  "Empty input is valid."
  (t.is true))

Assertions#

Use t.is for assertions:

(t.is true)
(t.is (> score 10) "score should clear the bar")
(t.is (= (+ 2 3) 5))
(t.is (not failed?))

t.is records failures through Odin's testing package and returns the boolean result from the underlying assertion helper.

Equality forms of shape (= actual expected) use value-aware reporting when possible, so failures can show both sides. Ordinary boolean expressions are checked as true or false.

Context#

Use t.testing to add a message around a group of assertions:

(t.deftest user-score
  (t.testing "new users"
    (t.is (= 0 initial-score))
    (t.testing "after bonus"
      (t.is (= 10 final-score)))))

Nested contexts are joined in failure output. The context is scoped with defer, so it is popped even if the body returns early.

Table Checks#

t.are repeats one assertion shape over rows of values:

(t.deftest squares
  (t.are [x expected]
    (= (* x x) expected)
    1 1
    2 4
    3 9))

The binding vector must be non-empty. The remaining values are consumed in rows the same size as the binding vector; if the row is incomplete, Kvist reports a macro expansion error.

Fixtures#

Fixtures affect tests defined later in the same package file.

Use :once for setup that should run before the first wrapped test body:

(defvar once-ran 0)

(defn once-fixture []
  (set! once-ran (+ once-ran 1)))

(t.use-fixtures :once once-fixture)

:once fixtures are setup-only. They do not receive a teardown continuation.

Use :each for wrappers around every later test:

(defn each-fixture [t: ^testing.T, body: fn [t: ^testing.T]]
  ;; Put setup here.
  (body t))

(t.use-fixtures :each each-fixture)

Each :each fixture receives the current ^testing.T and a body proc. Call (body t) to run the test body. If the fixture allocates resources, use ordinary Kvist cleanup patterns such as defer.

Ownership In Tests#

Test code is still normal Kvist code. If a helper returns owned memory, clean it up, usually with :defer or defer:

(import arr "kvist:arr")

(t.deftest generated-values
  (let [xs (arr.range 0 4) :defer]
    (t.is (= (count xs) 4))))

The test package does not hide ownership or allocator rules.

Property-Based Tests#

The property-based suite is a separate Odin runner under tests/pbt. It uses the pbt package as a test-only dependency; neither the Kvist compiler nor programs built with Kvist depend on it.

For local development, place the pbt repository next to Kvist as ../pbt and run:

./scripts/test_pbt.sh --text

Point KVIST_PBT_ROOT at another checkout when needed:

KVIST_PBT_ROOT=/path/to/pbt ./scripts/test_pbt.sh --text

The script caches the Kvist compiler, compiled targets, and PBT runner under the ignored tmp/pbt-cache directory. Cache entries are separated by workspace, Odin version, and PBT checkout, and each artifact is rebuilt when a source file or source directory is newer. Set KVIST_PBT_CACHE_DIR to move the cache or KVIST_PBT_REBUILD=1 to force a complete rebuild. Explicit target environment variables still bypass the corresponding cached target.

The runner accepts PBT options such as --property, --tag, --num-tests, --seed, --replay-seed, and --replay-choices. CI checks out an exact PBT commit under .tooling/pbt so the test dependency is reproducible.

The reader properties generate recursive forms, escaped string and regex literals, reader sugar, and discarded forms. The same generated model is also rendered both compactly and with varied whitespace, commas, and comments; both renderings must produce the same normalized CST. Targeted corruptions exercise missing, mismatched, and extra delimiters as well as unterminated string and regex literals, and require bounded reader diagnostics.

The EDN property compiles a small Kvist target and sends generated EDN values to it over stdin. The target requires structural read(write(value)) equality and idempotent canonical output, and the runner checks that a second process roundtrip produces the same bytes. scripts/test_pbt.sh builds this target automatically; set KVIST_PBT_EDN_TARGET to reuse an existing binary.

The stateful Data map property generates shrinkable command sequences over a small independent Odin model. After every assoc, dissoc, or lookup, a compiled Kvist target reports all modeled key slots. The property checks the complete resulting state, input immutability, and an internal EDN roundtrip. The script builds this target automatically; set KVIST_PBT_DATA_MAP_TARGET to reuse an existing binary.

A second stateful Data property models two-level maps and checks sequences of assoc-in, update-in, get-in, and dissoc-in. It covers both existing and missing paths, including creation of intermediate maps, preservation of empty parent maps, and sibling retention after deletion. It checks parent shape, the queried value, the complete nested state, and input immutability after every command. Set KVIST_PBT_DATA_NESTED_TARGET to reuse its compiled target.

The stateful sequence property switches between vector and list Data while checking conj, append, indexed assoc, pop, nth, peek, list, and vec against an independent bounded sequence model. It covers valid vector updates, out-of-range reads, empty peeks, and the different list/vector stack ends. Set KVIST_PBT_DATA_SEQUENCE_TARGET to reuse its compiled target.

The native set property generates duplicate-rich integer inputs and compares kvist:set with a finite-domain bitmask model. It checks pure and mutating union, intersection, difference, add, and remove operations, plus subset, superset, disjointness, membership, cardinality, and input immutability. Set KVIST_PBT_SET_TARGET to reuse its compiled target.

The Data transform property compares eager sequence helpers with an independent bounded model. It checks mapping, indexed mapping, filtering, take/drop, remove/keep, indexed keep, mapcat, split-at, reverse, interleave, rest/butlast, distinct and distinct-by, membership, interpose, take-nth, and concat. It also checks into ordering for vectors and lists, duplicate elimination for sets, and the identities concat(split-at(n, xs)) = xs and reverse(reverse(xs)) = xs. Generated counts cover negative and oversized values, while callback keys exercise collisions and negative remainders. Set KVIST_PBT_DATA_TRANSFORM_TARGET to reuse its compiled target.

The native map property compares kvist:map with a finite-domain reference model. It checks pure and mutating assoc, dissoc, and merge operations, lookup and defaults, membership, keys and value projections, zip truncation, duplicate keys, cardinality, and input immutability. Map iteration order is deliberately excluded from the model. Set KVIST_PBT_MAP_TARGET to reuse its compiled target.

The Data aggregate property checks left-to-right reduction, frequencies, count-by, group-by, index-by, and reduce-kv against an independent model. Generated modulo keys include negative values; groups must preserve input order, index-by must retain the last item, and frequency maps must reduce back to the original count and sum. Set KVIST_PBT_DATA_AGGREGATE_TARGET to reuse its compiled target.

The Data scan property checks first-match search, indexed search, min/max by key, boolean scans, take/drop-while, stable sorting, fixed partitions, partition-all, and partition-by against an independent model. Generated inputs include observable equal sort keys, missing searches, non-positive partition sizes, and incomplete trailing partitions. Set KVIST_PBT_DATA_SCAN_TARGET to reuse its compiled target.

The Data map transform property checks select-keys, merge and merge-with, key/value/entry callbacks, entry filtering, and into against a finite-domain model. Generated inputs force transformed-key and source-entry collisions. It also reconstructs maps through both entries and paired key/value projections. Set KVIST_PBT_DATA_MAP_TRANSFORM_TARGET to reuse its compiled target.

The stateful Data set property checks conj, append, membership, cardinality, and set-to-vector/list-to-set conversions against a finite-domain bitmask model. Every command also verifies input immutability and an EDN roundtrip; duplicate insertions must leave the set unchanged. Set KVIST_PBT_DATA_SET_TARGET to reuse its compiled target.

The Data accessor property generates every runtime Data kind with shallow, shrinkable payloads. It checks the one-hot type predicates, kind keywords, primitive accessor roundtrips, describe metadata, collection boundary accessors, map entry access, tagged payloads, and success/error metadata from the primitive decoders. Set KVIST_PBT_DATA_ACCESS_TARGET to reuse its compiled target.

The typed decode property generates valid nested configuration documents and targeted single corruptions across required fields, enums, nested structs, and typed dynamic arrays. data.decode and data.validate must agree, failures must report the modeled path/kinds/enum metadata, and successful native values must match independent summaries of the generated input. Set KVIST_PBT_TYPED_DECODE_TARGET to reuse its compiled target.

Compiler-semantics properties live in a separate slow runner because every case invokes the Kvist compiler and Odin toolchain. Run its default 25 cases per property with:

./scripts/test_pbt_compiler.sh --text

The generators build bounded integer, floating-point, boolean, escaped-string, native-array, map, set, struct, enum, and tagged-union expressions containing arithmetic, comparisons, logical operators, string transforms, literals, selectors, casts, indexing, lookup, membership, slicing, destructuring, field access, type-payload cases, value updates, mutation, if, typed-result let, function calls, anonymous functions and captures, pointers and aliasing, multi-return bindings and guards, cond, case, for, while, break, continue, defer, structural Data patterns and destructuring, and ->. The core-macro cases additionally cover ->>, cond->, as->, doto, when-let, if-let, when-ok, and if-ok, including single evaluation and short-circuiting across chained value/boolean and value/error bindings. Call-resolution cases combine positional, reordered named, mixed, and defaulted arguments with generic specialization and global, generic, and local overload selection. Dedicated cases verify that and and or short-circuit before an unsafe division. Each program is compiled and executed, and its output is compared with an independent Odin model. The runner supports the same replay and count options as the main suite; set KVIST_PBT_COMPILER or KVIST_PBT_COMPILER_EXPRESSION_SOURCE to override its cached compiler or integer/boolean source fixture. Set KVIST_PBT_COMPILER_STRING_SOURCE to override the separate string fixture; this keeps the kvist:str package cost out of non-string compiler cases. The script retries the known transient Odin Queue($T=string) type-check assertion for at most 32 total attempts. Other compiler failures are not retried, and the assertion remains an error if all 32 attempts fail. Compiler cases have a 120-second outer process timeout so the bounded retry sequence can finish before PBT classifies it as a timeout.

The compiler runner also generates invalid expressions directly against the frontend library. It covers invalid arities, missing case defaults, mismatched branch types, non-assignable mutation targets, removed forms, and statements in expression position. Every rejection must retain its diagnostic category and an in-bounds span attributed to the generated eval source.

Examples#

View this page on GitHub